The present invention relates to the field of lighting and more particularly relates to a variable color light projector used, for example, on a stage for performing shows.
Devices which allow variable lighting effects and use color filters arranged in a white light beam have long been known. For example, use of a disc comprising a series of filters arranged in a ring around a rotational shaft driven by a motor makes it possible to position a filter of the desired color in the light beam emitted by a projector. The choice of colors is limited to five or six filters, in most cases. Another drawback is that it is unavoidably necessary to pass through the color or colors that are arranged between the successive filters chosen.
Another known device makes it possible to superpose filters in the light beam, but it has the drawback of a significant loss of intensity.
A system has more recently been developed which uses color gelatins of square shape which form a strip, and each end of the strip is fixed to a motorized roller. By advancing the strip from left to right, or vice versa, the desired color light is obtained. It is therefore necessary to pass through all the intermediate colors in order to obtain the one located at the end of the strip.
All the devices described so far have the further drawback of producing a relatively large amount of noise because of their use of motor mechanisms for advancing the colors.
Finally, a device is known which comprises a set of filters and dichroic mirrors arranged in the light beam of three lamps, one mounted in the axis of the projector and the others radially with respect to this axis, respectively. This apparatus makes it possible to reproduce any desired color instantaneously because it allows mixing. However, it has the drawback of low luminosity, because of the superposition of the filters and of the dichroic mirrors in the actual body of the apparatus. Because of the high temperature reached by known devices, it is not possible to increase their intensity because the electronic parts do not withstand a temperature above 80.degree. C.